Heterosis and combining ability for seed yield, oil content and other quantitative traits in sunflower, Helianthus annuus L.*

The genetic analysis of line x tester crosses forming 30 hybrids from five CMS lines and six restorers revealed that SCA variances were predominant in the inheritance of seed yield, oil content and for most of the quantitative traits indicating the role of non-additive genes. The parents CMS 17 A and DCMS 51A found to be good general combiners for seed yield, hull content, volume weight, number of filled seeds, 100 seed weight, days to maturity, number of leaves/plant, head diameter, plant height, days to flowering and oil content, while CMS 234 A was a good general combiner for hull content, oil content and volume weight. The tester RHA-6D-1 exhibited high gca for 100-seed weight per cent seed filling and oil content while R-298 for number of filled seeds/head volume weight and seed yield The hybrid CMS 234A X RHA 95-C-1 had significant sca effects for seed yield and number of filled seeds/head. It also shown the highest better parental heterosis followed by CMS 234 A x RHA-6D-1 CMS 234 A x RHA-271, CMS 234 A x R-64 and CMS 234 A x R-298 for seed yield. All these hybrids found to have CMS 234 A as one of the parents and both parents in these crosses had low gca effects. The hybrids CMS 17 A x R-298, CMS 103 A x RHA-272, CMS 4546 A x RHA-271 and CMS 4546 A x RHA-272 exhibited significant better parental heterosis for oil content. However, none of the hybrids expressed positive and significant heterosis for both seed yield and oil content.